Hey everyone,
I have merged your reports of long matchmaking queues for Core Arena matches.
Let us know if you can find opponents in the Core Arena at other times during the day, or if you consistently get an error message, share a photo with us.
In the meantime, if the matchmaking has been stuck for you for an extended period, please try the troubleshooting steps from our iOS and Android guides under the Troubleshooting Steps section.
It might also help us isolate the cause of this situation if you try matchmaking using a different network than your usual one and using a different device; the network or the device settings might be involved.